body{
    color:red;
}
/*id选择器*/
#my_title{
    color:crimson;
}
h1{
    color:blue !important;
}
h1{
    color:yellow;
    
}
/*类选择器*/
.h1_color{
    color:blueviolet;
}
div{
    color:black;
    width: 100px;
    height: 100px;
}
